Cyclone separation is a kind of centrifugal sedimentation. Due to a centrifugal force, particulates in a vortex airflow are rotated at a high speed. As the rotational speed gets higher, the speed of centrifugal sedimentation of the particulates also becomes higher, such that the particulates can be separated from the airflow. Referring to FIG. 1, a conventional cyclone separator mainly includes a separation barrel 8. The separation barrel 8 is provided with an air inlet 81 on its wall surface, and has a lower portion whose diameter is gradually reduced and a top portion provided with an air suction channel 82. When in use, air containing particulates enters from the air inlet 81, and forms a descending vortex flow along the inner wall of the separation barrel 8. Then, a suction force is applied to the air suction channel 82 to form an ascending airflow in the separation barrel 8. Due to the weight of the particulates, the particulates cannot ascend with the ascending airflow and are deposited at the bottom of the separation barrel 8, thereby producing a dust collecting effect.
The dust filtering effect of the above conventional cyclone vacuum cleaner may be inadequate under certain circumstances. To reinforce the dust filtering effect of the cyclone separator, two approaches are proposed in the prior art. In the first approach, the volume of the chamber in the separation barrel is increased. In the second approach, a multi-layer dust filtering inner barrel is provided in the separation barrel, as disclosed in the Taiwan Patent No. I411422, Taiwan Publication No. 201340929, and China Publication No. CN103181741. However, the increased volume of the chamber inside the separation barrel inevitably expands the overall volume of the cyclone separator. On the other hand, the provision of the multi-layer dust filtering inner barrel also complicates the structure of the cyclone separator, meaning that not only maintenance is difficult but also periodical replacement of the dust filtering inner barrel may become another potential major issue. In the recent years, the cyclone separation technology is successfully applied to household vacuum cleaners. As household vacuum cleaners are required to collect only a small amount of dust or particulates, the above small-sized cyclone separator having a simple structure is sufficient. However, for industrial applications that demand dust filtering effects in industrial scales, the above conventional cyclone separator may fail to meet the corresponding industrial needs.